Kidney Function, Hormonal Control, and Nervous System Lecture Notes Vocabulary

Flashcards of key vocabulary terms and definitions from the lecture notes.

Fluid and Electrolyte Balance

Kidney function that regulates water and ion content in body fluids and maintains osmolarity to prevent cells from shrinking or swelling.

Blood Volume Regulation

Kidney function that ensures adequate blood volume for maintaining blood pressure and supporting cardiac output, balancing interstitial fluid volume to prevent edema or dehydration.

Excretion of Nitrogenous Waste

Kidney function that eliminates toxic nitrogen-containing molecules like ammonia, urea, and uric acid, produced during metabolism.

Erythropoietin

Hormone secreted by the kidney that stimulates red blood cell production.

Renin

Enzyme secreted by the kidney involved in regulating sodium ion concentration.

Renal Artery

Supplies blood to the kidney, branching from the descending aorta.

Renal Vein

Drains filtered blood from the kidney.

Renal Cortex

Outer region of the kidney.

Renal Medulla

Inner region of the kidney.

Renal Pelvis

Funnel-shaped structure that collects urine and funnels it into the ureter.

Nephron

Functional unit of the kidney responsible for filtration and urine formation.

Bowman's Capsule

Collects filtrate from glomerular capillaries in the nephron.

Proximal Tubule

Reabsorbs most filtered substances in the nephron.

Loop of Henle

Concentrates urine in the nephron; consists of descending and ascending limbs.

Distal Tubule

Further modifies filtrate composition in the nephron.

Collecting Duct

Transports urine to the renal pelvis.

Juxtamedullary Nephrons

Nephrons with long loops of Henle extending into the medulla, specialized for concentrating urine (10%).

Cortical Nephrons

Nephrons with short loops confined to the cortex, performing basic filtration and reabsorption (90%).

Podocytes

Specialized cells in Bowman's capsule with filtration slits that regulate filtration rate.

Apical Membrane

The surface of an epithelial cell that faces the lumen, contains microvilli to increase surface area.

Basolateral Membrane

The surface of an epithelial cell that faces the interstitial fluid and capillaries; contains different transporters and pumps.

Sodium-Potassium Pump

Located in the basolateral membrane, pumps out 3 sodium ions for every 2 potassium ions pumped in, requiring ATP.

Secondary Active Transport

Sodium's inward movement drives the transport of glucose, amino acids, and chloride against their concentration gradients.

Aquaporin

Water channels in cell membranes that facilitate water reabsorption.

Glycosuria

Excess glucose in the urine, often seen in uncontrolled diabetes mellitus.

Antidiuretic Hormone (ADH)

Hormone from the brain that controls collecting duct permeability to water.

Vasa Recta

Specialized capillaries that prevent the washing out of the medullary osmotic gradient.

Filtration

The process of fluid from the blood plasma passing into Bowman's Capsule

Reabsorption

The process of reclaiming needed nutrients, water, etc. back into the blood stream

Secretion

Wastes and excess substances actively transported from the blood into the tubule for excretion

Arginine Vasopressin (AVP)

Another name for Antidiuretic Hormone (ADH).

Renin-Angiotensin-Aldosterone System (RAAS)

Hormonal system that regulates blood volume and pressure by controlling sodium and water reabsorption.

Aldosterone

Steroid hormone that increases sodium reabsorption in the distal tubule and upper collecting duct.

Atrial Natriuretic Hormone (ANH)

Peptide hormone that increases sodium and water excretion, lowering blood volume and pressure.

Endocrine Signaling

Hormone enters blood, acts on distant cells (e.g., insulin, glucagon).

Paracrine Signaling

Acts on nearby cells via interstitial fluid.

Autocrine Signaling

Acts on the secreting cell itself.

Synaptic Signaling

Released by neurons at synapses, acts locally (Neurotransmitters).

Posterior Pituitary (Neurohypophysis)

Extension of the hypothalamus that releases ADH/AVP and oxytocin.

Oxytocin

Hormone that stimulates milk ejection from mammary glands and uterine contractions during labor; also associated with social bonding.

Anterior Pituitary (Adenohypophysis)

Endocrine cells controlled by hypothalamic hormones.

Portal System

Specialized vascular arrangement that concentrates hypothalamic hormones on target pituitary cells.

Prolactin

Hormone that stimulates growth of mammary glands during pregnancy and milk production after birth.

MSH (Melanocyte-Stimulating Hormone)

In humans, acts as a satiety signal in the hypothalamus, contributing to the feeling of fullness.

Endorphins

Naturally occurring opiates; inhibit pain and induce euphoria.

FSH & LH

Tropic hormones that control gonads (testes/ovaries), regulating gamete production.

TSH (Thyroid-Stimulating Hormone)

Tropic hormone that stimulates the thyroid gland.

ACTH (Adrenocorticotropic Hormone)

Tropic hormone that stimulates adrenal cortex.

Growth Hormone (GH)

Tropic and non-tropic hormone stimulates growth of bones, muscles, and all organs and also stimulates liver to release growth factors.

Thyroglobulin

Protein secreted into colloids by follicle cells.

T4 (Thyroxine, Tetraiodothyronine)

Thyroid hormone with 4 iodines

T3 (Triiodothyronine)

Thyroid hormone with 3 iodines that is more potent and converted from T4 in target cells.

Hyperthyroidism

Condition with high body temperature, sweating, irritability, and fidgetiness due to overstimulation of the thyroid.

Exophthalmos

Bulging eyes

Hypothyroidism

Condition with weight gain, lethargy, fatigue, intolerance to cold due to low thyroid hormone levels.

Cretinism

Irreversible brain and body underdevelopment in infants due to congenital iodine deficiency syndrome.

Adrenal Cortex

Outer layer of the adrenal gland that secretes steroid hormones.

ACTH (Adrenocorticotropic Hormone)

Stimulates the adrenal cortex from the anterior pituitary.

Mineralocorticoids

Regulate ions, especially sodium and potassium (e.g., aldosterone).

Glucocorticoids

Stimulates gluconeogenesis, promotes muscle catabolism, raises blood glucose, and strongly suppresses the immune system (e.g., cortisol).

Sex steroids

Androgens (e.g., testosterone), estrogens (e.g., estradiol), progestins (e.g., progesterone).

Adrenal Medulla

Inner layer of the adrenal gland that secretes epinephrine and norepinephrine.

Epinephrine

Hormone for short-term stress (seconds to minutes).

Cortisol

Hormone for long-term stress (hours to weeks).

GHRH (growth hormone releasing hormone)

Stimulates GH release.

Somatostatin (growth hormone inhibiting hormone)

Inhibits GH release.

GHRH (Growth Hormone Releasing Hormone)

Stimulates GH release.

IGFs (Insulin-like Growth Factors)

Promote cellular uptake of glucose and growth.

Gigantism

Excess GH in childhood, resulting in extreme height.

Acromegaly

Excess GH after bone growth stops, leading to thickened bones, enlarged facial features, and internal organ overgrowth.

GnRH (Gonadotropin-Releasing Hormone)

Released from the hypothalamus in pulses( especially at puberty), stimulates A.P. gonadotropes to secrete FSH/LH.

FSH (Follicle Stimulating Hormone)

Hormone that help stimulate gamete production and sex steroid hormones, produced by gonadotropins.

LH (Luteinizing Hormone)

Hormone that help stimulate gamete production and sex steroid hormones, produced by gonadotropins.

Testosterone

Lipid-soluble steroid hormone; diffuses into blood, binds carrier proteins, and acts on target tissues with androgen receptors.

Inhibin

Peptide Hormone secreted by Sertoli cells; specifically inhibits FSH secretion.

Ovarian Follicle

Contains the oocyte (egg)

Graafian follicle

Mature Follicle ruptures (ovulation), releasing the oocyte into the oviduct (Fallopian tube) where fertilization may occur.

Neuronal Signal

Brief changes in the electrical potential difference (voltage) across the plasma membrane of neurons.

Graded potentials

Local, variable in amplitude, decay with distance from stimulus, most common type of electrical signal in the nervous system.

Action potentials

All-or-none, rapid depolarizations that propagate along axons.

Hyperpolarization

Membrane potential becomes more negative (further from zero).

Depolarization

Membrane potential becomes less negative (closer to zero or positive).

Afterhyperpolarization

Potassium channels stay open longer than needed, causing the membrane potential to become more negative than resting.

Refractory Period

After an action potential, sodium channels are inactivated (inactivation gate closed), preventing immediate re-firing.

Myelin Sheath

produced by glial cells) wraps axons, leaving gaps called Nodes of Ranvier(Vertebrate Innovation)

Spatial View

Action potentials are not static; they propagate along the axon.

Capacitive current

When sodium enters, it neutralizes negative charges on the inside, releasing positive charges from the outside

Electrical Synapses

Presynaptic and postsynaptic membranes connected by gap junctions(pores allowing ions and small molecules to pass).

Chemical Synapses

Presynaptic Terminal: Contains vesicles filled with neurotransmitter.

Excitatory Synapses

Make postsynaptic action potential more likely (depolarization).

Inhibitory Synapses

Make postsynaptic action potential less likely (hyperpolarization).

Temporal summation

Repetitive stimulation of the same synapse in quick succession causes overlapping PSPs to add together, increasing the chance of reaching threshold.

Spatial summation

Simultaneous activation of multiple synapses at different locations on the neuron causes their PSPs to combine

Sarcomeres

functional units of muscle contraction, defined by Z lines/discs.